ColoCap: determining the diagnostic accuracy of colon capsule endoscopy compared to standard colonoscopy in patients at risk of colorectal disease.

Research question: What is the diagnostic accuracy of colon capsule endoscopy compared to standard colonoscopy? Background: Lower gastrointestinal symptoms attributed to colorectal disease are common. Early diagnosis of serious colorectal disease such as colorectal cancer (CRC), pre-cancerous growths (polyps) and inflammation is important to ensure the best possible outcomes for a patient. The current ‘gold standard’ diagnostic test is colonoscopy. Colonoscopy is an invasive and uncomfortable procedure. Some struggle to cope with it and require intravenous sedation and/or analgesia. It is also resource intensive, needing to be performed in specialist endoscopy units by a trained team. Unfortunately, across the UK the demand for colonoscopy is outstripping capacity and the diagnosis of colorectal disease is being delayed. A colon capsule endoscope (CCE) is an alternative colorectal diagnostic. It is a ‘camera in a pill’ that can be swallowed and which passes through the gastrointestinal tract, obtaining visual images on the colon. It is the size of a large tablet, about 3cm long and 1cm wide, rounded at both ends with a smooth plastic casing. There is now an established experience of CCE in the UK. As with colonoscopy the colon needs to be fully clean before taking the CCE. Clear fluids and purging laxatives need to be taken before the procedure. This can be difficult for some to tolerate but the CCE itself very rarely causes side effects, such as pain or vomiting. It should not be used in people who might have a narrowing in the bowel that could prevent its passage. CCE might provide a less invasive method to diagnose colorectal disease if found to be accurate and effective and provide a means by which to increase NHS diagnostic capacity. Aims & objectives: The aim of this study is to determine the diagnostic accuracy of CCE when compared to colonoscopy in representative and clinically meaningful cohorts of patients. An evaluation of the experiences of CCE for the patient and clinical team and an assessment of cost effectiveness will be undertaken. Methods: We will undertake three research workstreams (WS). In WS1 we shall perform a paired (back-to-back) study. Each participant will swallow the CCE and then later the same day they will have a colonoscopy. The study has been designed in collaboration with our Patient Advisory Group and as closely mirrors standard care as is possible. 973 participants will be recruited from three representative clinical contexts; suspected CRC, suspected inflammatory bowel disease and post-polypectomy surveillance. Up to 30 sites across the UK will be involved to ensure inclusivity. Measures of diagnostic accuracy will be reported along with CCE completion rates, number of colonoscopy procedures potentially prevented and adverse events, such as capsule retention. A nested sub-study of intra- and inter-observer agreement will be performed. WS2 will develop models of cost-effectiveness and WS3, the patient and clinician experience, with reference to acceptability and choice. Timelines for delivery: The study will run for 42 months with recruitment of participants over a 24 month period after a 9 month preparatory period. Anticipated impact & dissemination: The study findings will provide the evidence base to inform future colorectal diagnostic services across the UK, and internationally, and will be disseminated to the NHS, NICE, other clinical stakeholders and participants, patients and the public.